biology paper 1

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Cards (97)

what are carbohydrates broken down by?
amylase
what are carbohydrates further broken down by?
maltose
where is amylase found?
salivary glands
pancreas
small intestine
what are proteins broken down by?
protease
where is protease found?
stomach
pancreas
small intestine
what are fats (lipids) broken down by?
lipase
what are lipids broken down into?
glycerol
fatty acids
where are lipases found?
pancreas
small intestine
how does bile help with the digestion of lipids?
it emulsifies the lipids which increases the surface area for lipase enzymes to break them down
how to make a food solution for the food test practical:
take food sample and grind with distilled water using mortar and pestle to make paste
transfer paste to beaker and add more distilled water. stir so chemicals in food dissolve in water
filter solution to remove suspended food particles
test for starch: 
place 2 cm^3 of food solution into test tube
add few drops of IODINE solution
if starch present iodine goes from orange to blue/ black
what solution is used to test for starch
iodine
what colour does iodine go if starch is present
orange to blue/ black
test for sugar
add 2cm^3 of food solution
add 10 drops of BENEDICT'S solution
place test tube containing solution into beaker
half fill beaker with hot water from kettle
leave for 5 mins
if small amount of sugar present :green
if moderate amount: yellow
if high amount: red
what is the solution needed to test for sugar
Benedict's solution
what happens to Benedict's solution if sugar is present
from blue to either green yellow or red depending on the amount of sugar present
what type of sugar does Benedict's solution work for
reducing sugars e.g glucose
test for protein:
add 2cm^3 of biuret solution to food sample
if protein present turns purple/ lilac
what solution is used to test for protein
biuret solution
what colour does biuret solution turn if protein is present
from blue to lilac/ purple
test for lipids
grind food but dont filter solution as lipid molecules may stick to filter paper
add drops of distilled water and ethanol
if lipid present a white cloudy emulsion forms
what do you use to test for lipids
distilled water and ethanol
what happens to the solution is lipids is present
white cloudy emulsion forms
3 main nutrient  
carbohydrates
protein
lipids
what are the stages of the digestive system
mouth
oesophagus
stomach
small intestine
large intestine
faeces
what happens in the mouth during digestion
enzymes in saliva begin to digest starch into smaller molecules
what begins to digest in the stomach
proteins
why does the food in your stomach turn into fluid
increases surface area for enzymes to digest
what does the liver release
bile
what do the walls of the small intestine release
enzymes to continue the digestion of proteins and lipids
where is bile stored
gall bladder
how is the alveoli adapted for gas exchange
huge surface area as there are so many
thin walls
good blood supply: once oxygen diffuses into blood its rapidly removed ensures a steep conc. gradient
respariotry system 
trachea
bronchi
bronchioles
alveoli
how do farmers create conditions to increase photosynthesis
Using greenhouses to trap heat and provide artificial light
Pumping in carbon dioxide
Using paraffin heaters for heat and CO2
Applying fertilizers for essential minerals
Using pesticides to control pests
what is energy needed for loads of reactions in our cells, most of which are catalyzed by enzymes
Aerobic respiration
most efficient way to transfer energy from glucose, takes place within mitochondria
vector  
organism that transports the pathogen
pathogen 
micro-organism that can cause infectious disease
features of viruses  
not living organisms
not cells
organisms
10,000x smaller than animal cells
can't reproduce by themselves
health  
state of physical and mental well-being